Power crane, shovel, and the like



March 24, 1936.

POWER CRANE, SHOVEL AND THE LIKE 5 Sheets-Sheef l Filed March l5, 1954 41 4 .H i @W x@ @y NN QN QN NN March 24, -1936. o MCLEAN POWER CRANE,SHOVEL AND THEV LIKE Filed March 15, 1934 5 Sheets-Sheet 2 March 24,1.936. M0 MOLEAN 2,035,385

- POWER CRANE, sHoVEL AND THE LIKE Filed March 1,5, 1934 5 Sheets-Sheet3 March 24, 1936. o. MCLEAN POWER CRANE,

SHOVEL AND THE LIKE Filed March l5, 1954 5 Sheets-Sheet 4 INVENTOR March24, 1936. L, Q, MCLEAN 2,035,385

.POWER CRANE, VsHox/ELl AND THE LIKE Filed March l5, 1934 5 Sheets-Sheet5 zzz 9.

Patented Mar. 24, 1936 UNITED STATES P Arlzlv'rA OFFICE4 A I 3 Claims.

.My invention relates to shovels, cranes, excavating apparatus and thelike, and more particularly to such power machines that are inthemselves a, complete operable unit.

The general practice in the design of cranes, shovels, drag lines,trench hoes and similar mechanism is to provide achassis with arevolving table supported thereon by rollers which is arranged to carrythe` operator, the boom and the cable-Winding apparatus.

In the stationary power plant type of machine the motor is carried bythe chassis inthe Arear of the revolving table and the operating powerandsome of the controls for the boom and its associated parts aretransmitted from the' motor to the apparatus on the revolving tablethroughthe center thereof. When the operator Wishes to maneuver thistype of machine he is required to turn from the controls of his normalworking positionto operate the necessary levers on the chassis. Thusmoving or turning. of the whole machine involves a considerable loss ofoperating time. Again it is difficult to load and impossible to dig atthe rear of this shovel, as the stationary motor is in the way, which isan undesirable feature of this type of machine.

'I'he other general type of machine is known as the full revolvingmachine. The power plant of this type of machine is on the revolvingtable and the locomotive power is transmitted down through its pivotalaxis to the chassis and the driving mechanism.l The revolving table inthis type of machine is ordinarily rectangular in shape, the axis ofrotation not being at the center but approximately one-fourth of thelength of the table from the forward `end thereof.

The motor is located on the rear end of the table so that itsweighthelps to counterbalance the boom mechanism. When the table isrotated the rear end swings out over the chassis and the' propellingmechanism. rI'his feature is termed the tail swing of the machine.

Tail swing is a very undesirable feature especially if the operator ofthe shovel does not have full vision from his cab. He is unable to workin narrow'v or confined places owing to the large clearance required forthe rear of his machine l which might strike objects such as the truckscrane, shovel or similar mechanism that is' full revolving and does nothave any parts projecting beyond the propelling base.

I attain' this purpose by providing the machine with a rotary tablearranged to carry the power plant, the hoisting mechanism, and theoperator, which table does not extend beyond the propelling baseregardless of the position it may be in.

"'Ihis'impr'ovement is made possible by the a1'- rangement and design ofthe parts of the ma` chine and which lowerA the center of gravity oftable assembly.

I attain this feature by eliminating the ordinary table rollers thuslowering the center of gravity of the machine and rendering it morestable obviating the necessity of counterbalancing the boom mechanism bya weight which would have to extend a considerable distance from thecenter of rotation of the table.

To this purpose I employ a plurality of novel hook rollers adapted tooperate in a horizontal groove, or channel in the base of the mechanismand arranged to rotatably supportA the table against working thrusts,preventing it from tilting with respect to the base casting.

The hookrollers which support the table on the base casting are disposedin the same substantially horizontal plane as the central spindlebearing of the table.

ers ride has inwardly converging walls and the rollers are tapered orfrustro-conical, so that by properly adjusting the rollers axially thetable is eifectually prevented from tipping. The location of. the hook4rollers in the same` plane as that swing, also permits full vision ofthe operator` around the shovel so that he may quickly andadvantageously operate the machine, something which has not beenpractical heretofore on a full revolving shovel.

Again, the turntable is supported closely adjacent to the ba'se castingwhich permits theA buse of a short heavy spindle or stub shaft forcentering the turntable, making the mechanism stronger and more rigid. l

This feature also permits the use of a short vertical swing shaft whicheliminates the tendency for the swing shaft pinion to bind in the circlegear track.

All of these features are not attainable on the present design of fullrevolving machines of this nature because of the difference in theelevation of the supporting rollers and the spindle or stub shaftmechanism.

A further object of my invention is the provision of a combinationcrowding mechanism which is efficient and universal in its use on ashovel mechanism.

To complete the efficiency of operating the machine to the bestadvantage of the novel features therein I provide a pneumatic trip forthe dipper bottom controlled by the control levers making up a controlsystem which is novel in my machine.

Other objects, and also other novel features of construction, and alsoof arrangement of parts, will appear from the following description.

In the accompanying drawings, wherein I have illustrated a practicalembodiment of the principles of my invention, Fig. 1 is a side elevationpartly in section illustrating some of the novel features of myinvention.

Fig. 2 is a plan View of the same with the housing and cab cut away toshow parts.

Fig. 3 is an end view from the rear with the power plant removed and thehousing and cab in section.

Figs. 4 and 5 are sectional views on enlarged scale showing in detailthe structure of the hook rollers and their associated parts.

Fig. 6 is a side elevation showing the boom assembly.

Fig. 7 is a sectional View of the shipper shaft mechanism taken on theline 1-1 of Fig. 6.

Fig. 8 is a sectional view of the pneumatic tripper drum mechanism andits associated parts taken on the line 8-8 of Fig. 6.

Fig. 9 is a plan view of the turntable, parts of which are broken away,showing a modification of the shaft assembly.

Fig. 10 is a side elevation looking from the right in Fig. 9.

Fig. 11 is a side elevation, partly in section, looking from the left inFig. 9.

Referring to the drawings, I0 represents a standard propelling base orcrawler mechanism consisting of the frames which extend longitudinallyof the crawler mechanism and are arranged Ato rotatably support thecrawler link belts I2 by means of the end driving sprocket gears I3 andthe opposite end idler sprockets I4.

The under sides of the frames are provided with a series of idlerload-carrying rollers I5 which are arranged to ride on the interior ofthe crawler belt I2 as it passes beneath the frame between the endsprockets, thus carrying the load of the mechanism. 'Ihe top idlerrollers I6 are provided to carry the weight of the crawler belt I2 oidprevent it from sagging between the end sprockets.

The alined shafts I1 support the belt-driving sprockets I3 and areprovided with the chain sprockets I8.

The frames I I of the propelling base are rigidly connected by the crossbeams or members I9,

which are arranged to carry the entire shovel mechanism.

arranged to be secured to the beams I9 by means of the bolts 22. Thecircular perimetral surface of the base casting is provided with anannular groove or channel track 23, the upper and lower surfaces orsides 24 and 24' of which converge inwardly to receive a conical roller.

25 represents an internal annular gear track cut on the upper internalface of the casting and arranged to receive a rotating pinion. The basecasting 20 is provided with the radial spokes 26 terminating in thehollow hub or spindle 21, said spokes being below the gear track, asshown in Fig. 3.

28 represents a pair of brackets depending from the casting 20 at eachside thereof and arranged to support the housing of the lower horizontalpropelling shaft mechanism. The outer ends of the propelling shafts areprovided with the chain sprocket gears 29 arranged for driving thesprocket gears I3 of the propelling base by means of the chains 30. l

The propelling shafts are provided with the brakes 3|, inwardly adjacentto the brackets 28, which brakes are arranged to be separately operatedto prevent the rotation of either or both of the propelling shafts forsteering the machine vwhen traveling or for locking both propellingshafts to prevent movement of the propelling base.

32 represents the differential housing ar.

ranged for carrying the differential mechanism of the lower horizontalpropelling shafts. The differential housing 32 is secured to the underside of the base casting 20 at the center thereof. The differentialmechanism is of a design similar to those used on motor vehicles and isnot therefore shown in detail. The beveled pinion of the differential issecured to the lower end of the tubular drive shaft 33.

The drive shaft 33 is hollowed to permit the passage of a plurality ofcoaxially arranged air lines (not shown) therethrough for operating thepneumatic brakes 3| or other means for operating the brakes.

The drive shaft 33 extends up through the spindle 21 and is supportedtherein at its upper end by the antifriction bearings 34.

35 represents a. circular revolving table of the -shovel mechanism whichis arranged to carry the power plant and all the mechanism and controlsfor operating the shovel. 'Ihe center of the under side of the revolvingtable is provided with the hub 36 having the bearing bushing 36 which isarranged to rotatably engage the exterior surface of the Spindle 21,thereby maintaining the table on its centered pivoted connection. Thehub 36 is adequately strengthened or braced by the radial ribs 31 whichterminate in the annular depending flange member 38 of the rotary able.

39 represents an end plate secured to the upper surface of the gentlerof the table and which is arranged to carry thm end thrust bearing ofthe beveled pinion 4|) secured on the upper end of the drive shaft 33.5| represents a pressure grease fitting screwed into the plate 39 foradmitting lubricant to the bearing 34.

The rotary table 35 is supported by a plurality of oppositely disposedand arcuately arranged tapered or conical rollers 42 which ride in thetrack 23 and are arranged to engage the surfaces 24 and 24' thereof. Theterm channel track is employed to indicate a track having upper andlower engaging surfaces. -Said rollers are rotatably supported by meansof the brackets i3 depending from the table 35 and radially adjustabletherewith.' 'Ihe brackets may be provided with a horizontal T-shapedyportion as at 44 arranged to slide in a complementary T-shaped slot 45in the box-like structure 46 which may be integral with or secured inany suitable manner to the underside of the table 35. 'Ihe underside ofthe box has fastened thereto the back-up plate 41 as by the bolts 48,vwhich plate is arranged to clamp and receive with the T- shaped slot ofthe box any upward thrusts froml the brackets 43. The table is slottedas at 49 to receive the bolts 5I! which screw into and lock the brackets43 in position after they have been adjusted in the annular groove 23.

5| represents lugs depending from the table 35 at a point radiallybeyond the brackets 43 and the box structure 46. These lugs are providedwith threaded holes for receiving the radial adjusting screws 52. Theinner end of the adjusting screws 52 are arranged to move the brackets43 radially and are provided with lock nuts to hold them in place afterthe adjustment is made.

The depending portion 53 of the brackets 43 is provided with thenon-rotatable shaft 54 which carries the conical rollers 42 on theantifriction bearings 55. Fig. 2 of the drawings shows the preferredarrangement of these supporting rollers and their radial adjustingmechanism wherein four rollers are each radially e positioned about thetable at an angle' of approximately twenty degrees from a planebisecting the circular table and the boom of the shovel. Whenlthemshovel is working or digging the fore i rollers support thedownward thrust by riding on the lower side 24' of the track 23 whilethe aft rollers take the upward thrust, or vice versa when the thrustsare reversed, thus relieving the spindle 21 from bending strains.Therefore the revolving table is rotatably supported by the rollers 42and the conventional Vturntable rollers which in common practice areinterposed between the base casting andthe turntable are eliminated. y

It will be noted that the construction described enables the centerbearing of the turntable to be lowered so that the plane of the axes ofthe rollers 42 will intersect said bearing, thus reducing the bendingstresses effective on the spindle 21 to aminmum. d

56 represents the motor or power plant which is secured on the rear ofthe table and transversely thereof. The radiator 51 and the crank 58extend beyond the covering or hood 59. The other end of the motor isprovided with the transmission as indicated at 60 which 'has the usualgear shifting lever and `clutch mechanism (not shown).

The drive shaft 6| extends beyond the transmission 66 and is providedwith the sprocket gear 62 which rotates counterclockwise in Fig. 1,

and is arranged to drive the sprocket gear 63 of the first intermediatedrive shaft 64 by the chain 65. The shaft 64 is journaled in suitablebearings on the table 35. The sprocket gear 62 is of smaller diameterthan the sprocket gear 63 and eects a reduction in speed of the rstintermediate driven shaft 64.

The shaft 64 is provided with the multiple belt drive pulley 66 arrangedto drive the air compressor 61 mounted on the table 35, by means of thebelt 68.

69 represents a sprocket gear on the shaft 64 for driving, through themedium of the chain 1|l, the sprocket gearsl 1|, 12, and 13 of theVupper horizontal propelling shaft14, the horizontal n 3 swing shaft 15,and the mam hoisting shaft 1s.

' respectively, all of which shafts are arranged .inwardly andoppositely disposed flange members 11 arranged to support brake bandmechanism applicable to operate on the drum mechanisms carried by theshaft 16.

The upper horizontal propelling shaft 14 is positioned directly over thecenter of the table 35 and rotatably carries the beveled gear 18arranged to mesh with the pinion 40 on the upper end of the shaft 33.Upon engaging the mechanical clutch 19, xed to the shaft 14, with itscomplementary part in the beveled gear 18, power may be transmitted fromthe shaft 14 to the shaft 33 and the differential mechanism, therebyoperating the lower horizontal propelling shafts for driving thesprocket vgears of the crawlers to.

effect vpropulsion oi:`- the mechanism. Thedirection of travel of thecrawlers may be effected by the shifting of the usual gears intransmission 60.

The rotary shaft 14 is also employed as second intermediate drive shaftfor operating the boom hoist drum 80. This is effected by engaging themechanical clutch 8|, fixed to the shaft 14, with its complementary partin the beveled gear 82 lrotatably mounted on the shaftv 14 and whichmeshes with the beveled pinion 83 keyed to one end of the inclined shaft84 suitably journaled from the table 35. The other end of the shaft 84is provided with a worm pinion 85 in mesh with the worm gear 86 on thehorizontal boom hoist shaft 81 which carries the drum 80 and isjournaled on the underside of the table 35. The drum 80 is provided withthe cable 88 which is employed to raise and lower the boom and extendsup through the table 35. lSince the boom hoist drive mechanism includesa meshing worm pinion and gear it is necessary that it be positivelydriven in both directions. This movement is accomplished by shifting thegears in the transmission 60 as in the case of. reversing the directionof the propulsion crawlers.

89 represents a sprocket rotatably mounted on the shaft 14 and which maybe caused to rotate therewith by engaging the pneumatic clutch 90, thelatter being operable by means of the air ram 9|. The sprocket4 89 isarranged to drive the sprocket 92 mounted on the crowd spool 93 by meansof the chain 94.' The Aspool 93 is rotatably mounted on the shaft 16 butmay be caused to rotate with said shaft by.energizing the pneumaticram9| to engage the clutch 90. The horizontal swing shaft 15 is providedwith `the opposed air rams 95 and 96 which operate Awill drive thebeveled gear Illl counterclockwise in Fig. 2, thereby swinging the table35 clockwise in Fig. 2. Similarly if the pneumatic ram 96 is 'energizedthe table 35 is caused to rotate counterclockwise.

The pneumatic rams 95 and 96 are controlled by operating a single leverin opposite directions so that only one ram may be energized at a. time.

Referring now to the main hoist drum shaft 16, which is at' the apex 'ofthe operating shaft assembly, |04 represents a pneumatic ram arranged tooperate the clutch |05 which imparts rotary movement to the main hoistdrum |06 rotatably mounted on the shaft 16 for winding the hoist cable|01 thereon.

|08 represents a pneumatic ram arranged tov operate the clutch |09 fordriving the crowd spool 93 in a counterclockwise direction in Fig. 1 onthe shaft 16. Thus by means of the clutch 90 the crowd spool 93 may berotated in a clockwise direction in Fig. l, while by means of the clutch|09 a reverse rotation of the crowd spool may be effected.

'I'he spool 93 is provided with the sprocket ||0 arranged to drive thesprocket by means of the chain ||2. The sprocket is fixed to the sleeve||3 which is rotatably mounted on the stationary boom hinge pin H4. Itis obvious that the direction of rotation of the sprocket is determinedby the selective energization of the pneumatic rams 9| and |08 which arecontrolled by a single lever operated in opposite directions aspreviously explained.

||5 and ||6 represent air pistons mounted on the brackets 11 and whichare arranged to operate the brake bands ||1 and ||8 of the main hoistdrum |06 and the crowd spool 93 respectively. These brake bands arearranged to retard the movement of their respective drum and spool or tolock the same against movement.

The stationary boom hinge pin ||4 is supported on the table 35 and inthe front thereof by means of the upstandng lugs ||9. The ends of thepin I |4 carry the base sockets |20 arranged to receive the compressionor front legs |2| of the boom hoist mast |22. The table 35 is providedwith the upstanding lugs |23 between which is attached the lower end ofthe tension or rear leg |24 of the mast' |22. The three legs of the mast|22 converge at their upper ends in the mast head |25 which is usuallyprovided with a pair of idler pulleys or sheaves |26 arranged to carrythe boom lmist cable 88 which starts from the boom hoist drum and passesover one of the mast sheaves |26 to a pulley at the outer end of theboom and returns to dead end the other mast sheave |26 as shown in Fig.1.

|21 represents a box type boom whose inner end is provided with the boombase castings |28 which are hingedly attached as at |29 to the boomhinge pin ||4 between the lugs I9. The other end of the boom is providedwith the boom cap casting |30 for supporting the idler boom hoist sheave|3| and the main hoist sheaves |32. The former carries the boom hoistcable 88 while the latter sheaves carry the main hoist cable |01.

Intermediate of its ends and on the upper surface thereof the boom hasadjustably secured thereto the shipper shaft assembly |34, a sectionalview of which is shown in Fig. '1. This assembly includes a shaft |35journaled in the bearings |36 secured to the upper surface of the boom.The pinions |31 which are securedto the shaft |35 on each side of theboom movably support the dipper sticks or handles |38 whose under sidesare provided with the racks `|39 arranged to mesh with and be driven bythe pinions |31. The outer ends of the shaft |35 rotatably support thebrackets or guides |40 in which the dipper sticks slide and which extendup along the outer sides of the sticks and project inwardly over the topand ride upon the upper surface thereof.

|4| represents a spool'or cable drum keyed to the middle of the shaft|35 between the bearings |36. The boom is cut away to receive theflanges |42 and |43 of the drum 4|. The perimeter of the flange |43 isprovided with sprocket teeth to receive the crowd chain |44 which isdriven by the sprocket |45 secured to the sleeve ||3 Aon the hinge pin||4.

'Ihus the dipper sticks |38 may be moved in by energizing the pneumaticram |08 which engages the clutch |09, driving the crowd spool 93counterclockwise in Fig. 1, thereby driving the chain ||2the sprocketthe sleeve ||3, the sprocket |45, the chain H4, causing the shippershaft |35 to move the dipper towards the boom. Again if the pneumaticram 9| be energized to engage the clutch 90 for driving the sprocket 89from the shaft 14 thereby rotating the crowd spool 93 in the opposite orclockwise direction, the dipper is moved out or away from the boom. Thepneumatic rams 9| and |08 are operated by the movement of a controllever in opposite directions. 'I'hus it is impossible to create aninterference between these movements by energizing both ramssimultaneously.

The outer end of the dipper sticks |38 are connected by the casting |38to which is hinged the dipper, shovel or bucket |48 which is providedwith the dipper hoisting block assembly |41 arranged to receive thehoisting cable |01.

The outer or remote end of the hoisting cable is attached to the drum I4| of the shipper shaft assembly and is wound several times therearound.The cable is then carried over one of the sheaves or idler pulleys |32in the boom cap casting, thence to the dipper hoisting block assembly|41 and back to the other sheave |32 of the boom can casting and thenceto the main hoisting drum |06. Thus lf the crowd chain assembly ispermitted to freely rotate by releasing the brake |'8 on the crowd spool43 the hoist cable |01 may be used for crowding out the dipper. Iheweight of the dipper at the end of the dipper sticks is then suicient tocause the dipper to drop unreeling the hoist cable that is wound aroundthe shipper shaft drum |4|. During this action the main hoist drum |06is locked so the movement of the dipper 1s out and slightly downward.Before the sticks are run completely out the main hoist drum is releasedand the cable |01 is permitted to unreel therefrom. 'I'he dipper wouldthen swing in an arc back towards the base of the boom and in theposition to dig, the sticks being almost all the way out. The pneumaticram |04 is then energized, which actuates the clutch |05, caus ing themain hoist drum |06 to reel-in the hoisting cable |01. The weight andthe resistance to movement of the material scooped up by the dipper isthen divided into two forces by the pull on the hoist cable |01. Part ofthe energy will be used in pulling the dipper forwardly and the restwill be used in unreeling the cable |01 from the shipper shaft drum 4|which forces the dipper sticks away froxnvthe boom, causing the dipperto crowd further into the soil or material to be removed. When theresistance of the material to the downward movement of the dipperbecomes greater than the resistance of the matcrial to the forward pullon the dipper the cable |01 will stop unreeling on the drum |4| andthedipper will be raised as it is drawn forwardly. When the resistance tothe downward movement of the dipper becomes les,\the sticks tend to rles' provided with windows softhat the Ioperatorhas a 4 clear vision in alldirections.

crow'd thedipper down to equalize'zthe load until the sticks are all theway out. termed the cable crowd out, "anddswveryfsuccessful because vofits uniformly eiiicient method 4of digging.

` The other method'for crowding out is by means of a positive drive, as-by driving out the dipper sticks by rotating movement -in Fig. 4aspreviously described. This method is not as efiicient as the rope crowdas the operator must divide the ,power between the hoisting and crowdingout actions at the operating shaft mechanism, and the result is that heis never able to balance the loads as automatically occurs with the"rope crowd method.

However the positive chain crowd is more satisfactory to draw the dippersticks in and I have.

therefore employed the best features of both methods to obtain what Iterm as a rope-chain crowd and the rope crowd feature must necessarilyemploy the chain crown-in feature to obtain a complete crowd function.

To complete` the operation of digging with a shovel I have provided thedipper with a pneumatic tripper mechanism for releasing the door of thedipper to permit the material to fall therefrom. Referring especially toFig. 8 to accomplish this function I employ a reel |48 journaled Y onthe hollow shaft above theshipper-shaft mechanism. Compressed,

|49 xed within the boom |21 air is fed from the table 35 to the shaft|49 by the tubing |50 which is connected therewith so as to open intothe hollow portion |5| vof the shaft |49. The shaft |49 is provided withthe ports |52 which form a communication between the hollow portion 5|of the shaftand the annular recess |53 in the bore of the reel |48 whichin turn is provided with a hose connection as shown at |54. 'I'he recess|53 is properly'sealed against the escapel of air by the annular sealingrings |55 and' is provided with adequate lubricating appliances. |56represents a helical spring secured at one end to the boom and at theother end to the reel |48.

This permits the unreeling of the hose- |51 from the reel as the dipperis moved out from the boom and draws the hose back onto the reel as thedipper is retracted.

|58 represents two pulleys mounted in the un'- der side of the boom forguiding the hose |51 therethrough.

'I'he other end of the hose terminates at the box |59 mounted on therear of the casting |38' and arranged to house the piston |60 which isprovided with a spring to maintain it in its retracted position. Whenthe compressed air is admitted to the tubing |50 it travels through therecess |53 of the reel and the hose |51 and forces the piston againstthe lever |6| which vrocks on its fulcrum |62, causing the other endthereof to strike the anged head of the sliding bolt |63 releasing thebolt from the lock slot |64 of the dipper. The door of the dipper thenswings away on its hinges |65 pivoted at |66 and the material falls-from the dipper. As the dipper is returned to the clearance for theextension of parts therethrough. f

At the side, the right in Fig. 3, it is stepped down to lform the floorof the cab 59 in which the operator sits or stands. The upper walls ofthe cab are the chain .|44 a clockwise journaled in the bearings |1I |81represents the `chain crowd and swing control lever within the cab,which actuates pneumatic valves to zenergize the respective rams foroperating the clutches to l engage the selected crowd and swing parts'lfgthe mechanism. Forward movement of the lever operates the dipper tocrowd-out andthe rearward movement operates `the pull-in of the dipper;while movement of the lever tor the left causes the turntable to rotatecounterclockwise swinging the boom to theleft and movement of the leverAto the right swinging the boom to the right. When the lever is in itsneutral position with respect to the crowd function the crowd brake I I8is automatically applied.

|88 represents the 'main hoist drum and trip control lever also in=thecab. By moving this lever forward the brake I|1 `of the main hoist drum|08 is released and the weight of thedipper is permitted to unreel thecable therefrom. Moving this lever to the rear operates the ram |04 toreelin the cable |01, and moving it right operates the trip mechanism.The operator thus has full control of the digging operations of themachine through the medium of two small universal levers. The levers |61and |88 may conveniently be of the general type disclosed in myLettersPatent No. 1,711,896, issued May '1, 1929.

" Referring to Figs. 9 to 11, inclusive, I illustrate the practicalembodiments ofmy invention as a modification thereof. The parts similarto those discussed above are being designated by the same referencenumerals.

|10 represents the upper horizontal drive shaft and |12, and|13represents .the main hoist drum shaft journaled in the bearings |14 and|15. These shafts are driven from the first intermediate shaft 64 bymeans of the sprocket 89, by the chain 10 and the sprockets 12 and 1| onshafts |13 and |10, respectively.

4As shown in Fig; 1`0, the chain 10 runs around the sprocket 12 of theshaft |13, rotating said shaft in a counterclockwise direction, 'andmeshes with thel sprocket 1| from below, rotating the shaft |10 in aclockwise direction. l

The shaft |10 is provided with the beveled gear 18 arranged to mesh withthe pinion 40 for propeiling -the machine when the toothed clutch member|16 is moved to the left. Moving the clutch |16 to the right drives thebeveled gear 82 which is meshed with the beveled pinion 83 on the-inclined shaft 84 for driving the boom hoist drum 80, on the shaft 81through the meshed worm and gear 85 and 88.

The shaft |10 is provided as before with the chain crown-out mechanism,which comprises the pneumatic ram 9| for operating the clutch 90 todrive the sprocket 92 and the crowd spool 93 in a clockwise direction.

On the other side of the bearing |1|, the shaft |10 is provided with thesprocket |11 which may be made to rotate with the shaft by energizingthe pneumatic ram |18 fo'r operating the clutch |19. The sprocket |11drives the chain |80 in a counterclockwise direction in Fig. 11, whichin turn 'drives the sprocket |8| fixed to they horizontal with thebeveled gear |0| secured td the upper end of the vertical swing shaft|02. Thus the clutch |19 on the shaft |10 operatesthe vertical 9|, |04and |08 are fastened to swing shaft 9, revolving clockwise. Y

Similarly, the shaft |13 is provided with the pneumatic ram |84 arrangedto operate the clutch |85 to rotate the sprocket |86 in a clockwisedirection in Fig. 11, thus driving the chain |80, the sprocket |8|, thehorizontal swing shaft |82, and the beveled pinion |00 in acounterclockwise direction. 'I'he vertical swing shaft |02 is therebyrotated in a counter-clockwise directon in Fig. 9 and the table 35 swungto the right.

'Ille rams |18 and |84 are supported by the brackets |81 which may bebolted or otherwise fastened to the table floor. The other rams, thebearings |1|, |15 and |14, respectively.

The main hoist drum |06 and its operating mechanism is the same as thatdescribed above except that it is in the reversed position on the shaft|13.

The crowd spool 93 and the crowd-in mechanism is also the same as beforeexcept that it is mounted on the opposite side of the main hoist drumshaft.

The reversal of these parts is due to the pro'- |02 in a clockwisedirection in Fig. the table 35 to the left or countervision of thesingle clutch member |16 which is employed, when moved to, the left, topropel the mechanism and is arranged to lower or raise the boom whenmoved to the iight.

The modication illustrates a novel method of reducing the shaft assemblyto an arrangement in a substantially single plane which provides forbetter vision for the operator and lowers the center of gravity of themachine:

Fig. 11 also shows a modification in the manner in which the turn-table35 is journaled toI the base casting 20. |88 represents a hollow stubshaft integral with the table 35 and arranged to be journaled invertical bearing |89 held by the hub |90 of the base casting 20. Thespokes, or ribs, 26 are arranged to support the hub |90 and providereinforcement for the base casting 20. The internal bearing surface ofthe bearing |89 may be convex, its walls converging lslightly inwardlyfrom the ends to a circle or zone in the center thereof. 'I'his zone isin the same plane as the axes of the supporting rollers 42. If the tableis tipped slightly due to the required clearance of the rollers 42 inthe annular track 2'3, the stub shaft |88'will roll about an imaginaryhorizontal axis, on the internal convex surface of the bearing |89 andthus avoid transmission of any bending strains to the hub |90 of thebase casting 20.

The channel track and hook roller construction, provide the importantfeatures of my invention, together with the mono-plane table supportingfeature which permits the lowering of the center of gravity of theturn-table and the mechanism mounted thereon, eliminating the use of theordinary turn-table supporting rollers and the long spindles forcentering the turn-table.

'I'his invention permits the use of a power plant mounted on a circularVturn-table, no part of which extends beyond the rim of the table butall within the spread of the ordinary crawler propelling base.Heretofore this feature was impractical, as the supporting rollers forthe rotary table positioned the turn-table considerably above the ringgear casting, requiring an extended spindle which was subject tobreaking stresses if the boom were not counterweighted by a weight orportion of the apparatus extended from the spindle to form a lever armmuch greater than that of the boom. 'I'his feature necessitatedconsiderable tail swing.

My invention permits the assembly of the rotary table in close relationto the ring gear,

which eliminates the strains on the spindle and drops the center ofgravity, increasing the efciency of the machine very materially andeliminating any tail swing whatsoever.

I claim:

1. 'I'he combination with a base member, an annular exterior channeltrack carried by said base member, a turntable member, a plurality ofrollers carried by said turntable and engaging said track for supportingthe turntable, of universal bearing means between said members tomaintain them in coaxial relation, said bearing means comprising a.vertically disposed arcuate bearing surface, the center of theclosed-curve contact between the bearing surface being disposed in theplane of the axes of said rollers.

2. The combination with a base member, an annular exterior channel trackcarried by said base member, a turntable member, a plurality of rollerscarried by said turntable and engaging said track for supporting theturntable, of a central bearing element on one of said members, acentral stub-shaft on the other of said members arranged to be insertedin the bearing element, an arcuate bearing surface interposed betweenthe bearing element and the stub-shaft to provide for universal movementtherebetween, the axes of said rollers being in a plane that intersectsthe center of the circular-line contact between said arcuate bearingelement and said stub-shaft.

3. The combination with a dirigible chassis, a

base member mounted on the chassis, an annular r channel track carriedby said base member, a turntable member, a plurality of rollers carriedby said turntable and engaging said track for supporting said turntable,of universal bearing means between said members to maintain them incoaxial relation, said 'bearing means comprising a vertically disposedarcuate bearing surface, the center of the closed-curve Contact betweenthe bearing surfaces being disposed in the plane of the axis of therollers, said bearing means being hollow to provide for the passage ofmeans for guiding and propelling the chassis.

LELAND O. MCLEAN.

